This paper deals with the phenomenology of magnetic reconnection during reversed-field pinch helical self-organization. Numerical results obtained by solving a three-dimensional nonlinear visco-resistive fluid model to describe the hot current-carrying plasma are summarized. Magnetic reconnection manifests itself during the plasma dynamics, interrupting the persistence of quasi-helical states. The main signatures of magnetic reconnection in reversed-field pinches are discussed: partial conversion of magnetic into kinetic energy, current sheet formation, steepening of plasma current profiles, locking of the angular phases between different Fourier components of the magnetic field. The latter is recognized as the three-dimensional trigger of the reconnection events. Then the paper deals with the temporal scales of the process: low visco-resistive dissipation in the model, corresponding to high plasma current in the experiments, results in longer characteristic time between reconnection events. Furthermore, it is confirmed that the scaling of the reconnection rate is compatible with a modified Sweet–Parker model. A discussion of magnetic reconnection during the 2D simplified tokamak internal kink mode evolution, showing the development of secondary tearing instabilities, is presented and the similarities with RFP evolution are highlighted.

本文研究了反向场收缩螺旋自组织过程中的磁重连接现象。总结了通过求解三维非线性粘滞流体模型来描述载热等离子体的数值结果。磁重新连接在等离子体动力学过程中表现出来，打断了准螺旋态的持久性。讨论了反向场收缩中磁重新连接的主要特征：将磁部分转换为动能，形成电流片，使等离子体电流曲线变陡，锁定磁场的不同傅立叶分量之间的角相。后者被认为是重新连接事件的三维触发。然后，本文讨论了过程的时间尺度：模型中的低粘电阻耗散（对应于实验中的高等离子电流）导致重新连接事件之间的特征时间更长。此外，已确认重新连接速率的标度与修改后的Sweet-Parker模型兼容。讨论了二维简化托卡马克内部扭结模式演化过程中的磁重连，显示了二次撕裂不稳定性的发展，并着重指出了与RFP演化的相似性。